논문 상세보기
The infection of marine diatom Coscinodiscus wailesii by a parasitic protist from the Yongho Bay of Busan, Korea was observed during the diatom bloom events in 2017 through 2018. The morphological and molecular features suggested that the parasitic nanoflagellate Pirsonia diadema was responsible for the infection. During the study period, the parasite prevalence ranged from 0.3% to 3.3%, and infected C. wailesii cells were observed only at surface seawater temperatures ranging between 10.9 and 19.9°C, although the host population appeared at temperatures above 25°C. The parasite and host system was successfully established as cultures. Using the cultures, we determined the morphological features over the infection cycle, parasite generation time, parasite prevalence as a function of inoculum size, and zoospore infectivity and survival time. The diatom C. wailesii was readily infected by the parasite P. diadema, with a parasite prevalence reaching up to 100% and a zoospore to host inoculum ratio above 20 : 1. The survival and infectivity of the parasite zoospores decreased with age. While the zoospores could survive up to 88 hours, they quickly lost their ability to infect after 48 hours. These results could lead to a better understanding of the biology and ecology of the parasitoid infecting the giant-sized diatoms in coastal waters.
INTRODUCTION
MATERIALS AND METHODS
1. Sampling
2. Parasite prevalence in the field
3. Parasite and host culture systempreparation
4. Light microscopy
5. Scanning electron microscopy
6. DNA extraction, PCR, sequencing
7. Alignments and phylogenetic analyses
8. Parasite prevalence as a function ofinoculum size
9. Survival and infectivity of parasitezoospores
RESULTS
1. Environmental condition
2. Dynamics of host abundance and parasiteprevalence
3. Parasite morphology and development
4. Parasite prevalence as a function ofinoculum size
5. Zoospore survival and infectivity
6. Molecular phylogeny
DISCUSSION
REFERENCES
